The big news of the day, not just for A's fans but for baseball fans in
general (due to the lack of other news), was the trade of Vin Mazzaro and Justin
Marks to the Royals for David DeJesus.

DeJesus is a soon-to-be-31-year-old lefty outfielder who has played his
entire career in Kansas City with little distinction. He finished sixth in the
Rookie of the Year voting in 2004, as Oakland's own Bobby Crosby took home the
award (that by all rights should have gone to Zack Greinke, who posted a 3.97
ERA in 145 innings). He led the league in hit-by-pitches in 2007 and was
top-ten in triples from 2005-2009. Lack of distinction doesn't mean he's not a
useful player, though -- his career on-base percentage ranks in the top fifty of
active players and he is regarded as a fine defensive outfielder, capable of
good work in center or excellent in a corner. At his peak (2005-2008), he was a
two-and-a-half-win offensive contributor. Add that to whatever his glove is
worth (half a win? A win? More?) and you get a guy absolutely worth the $2M to
$3.6M he was making. He only played 91 games in 2010, however, as he went down
in late July with a thumb injury that he never returned from. On the other
hand, according to Corey Dawkins's DL tool, he's
only been on the 15-day DL once in his career.

Bill James has DeJesus projected for a .340 wOBA next year (i.e. league
average), but that's a higher mark than Ryan Sweeney, Coco Crisp, or Conor
Jackson, and likely higher than whatever Travis Buck would project to if James
had projected him. Only Chris Carter of potential A's outfielders beats
DeJesus's projection, though park differences might have something to say about
that: StatCorner has Kansas City with a 104 wOBA factor for lefties, compared to
95 in Oakland. That's a pretty significant swing, likely enough to drop
DeJesus's projection down to basically the same range as Sweeney, Crisp, or
Jackson (but definitely behind Carter, who was already projected into Oakland,
where the RHB wOBA factor is even lower at 93).

So DeJesus is going to make $6 million to basically be the same as Ryan
Sweeney or Coco Crisp or Conor Jackson. Why do the deal? First: injuries. Every
person named in that sentence was hurt for significant periods of time in 2009.
Assuming you don't have the money (or will) to sign Jayson Werth or Carl
Crawford, or the trade chips to get whatever big bopper might be available, the
next-best idea is to get extra average players so that when guys get hurt,
you're not stuck playing Travis Buck, Matt Watson, Matt Carson, and Rajai Davis.
Or putting Adam Rosales, Jack Cust, or Jeff Larish into the outfield. The jump
from Jackson to DeJesus, in other words, is minimal (though the defensive bump
is nice). But if DeJesus or Crisp or Carter (my presumed starting outfield) goes
down, the drop-off to Conor Jackson is a very different thing than the drop-off to
Rajai Davis (who should be reduced to caddying for Chris Carter and
pinch-running for all and sundry).

Second reason you do the deal: Vin Mazzaro's value is at its highest point
right now. He's a supposed ground-ball pitcher who doesn't get ground balls. He
doesn't miss bats. His control is solid, but his walk rate isn't low enough to
make his K/BB stellar. He doesn't do Dallas Braden-like things with the glove
or holding runners. And on top of all this, he might, as Ken Arneson
posited earlier today on Twitter, be a dummy or a head-case -- see the weird
demotion to Sacramento late in 2010.

Mazzaro is likely not better than a million other guys who could step in if
the A's front-line starters go down, guys like Tyson Ross or Clayton Mortensen.
The question, then, is "who is Justin Marks"? And here's what I'll tell you: I
dunno. Baseball America had him 27th in the A's system coming in to 2010. He
was a third-rounder out of Louisville in 2009. BA called him "polished" but said
that he had no plus pitches, and tapped his upside as back-of-the-rotation
starter with the chance to reach that potential fairly quickly. John Sickels
game him a C+, a fine grade for a guy who hadn't even recorded a professional
out (he got into one game in rookie ball, giving up three hits and four walks
without retiring a batter). His writeup agreed with BA's, describing him as a
strike-thrower with better velocity than most finesse guys, but not enough to
call him a power-pitcher.

In other words, if things go right for Marks, he can grow up to be ... Vin
Mazzaro. A guy who won't kill you if you're using him as a 3rd or 4th starter,
but who isn't really pushing you to a championship either. These guys are
bellwethers, basically. If they're your 3rd starter, then say hello to 72 wins.
Fourth, you should be right around .500. Fifth, and you've probably got yourself
a very good rotation that can get you into the playoffs. If you trust your
player development team, these are guys you can trade because you can draft
three to five new copies of them every year in perpetuity.

I'm not going into a winners or losers discussion here. I'm not JC Bradbury,
but I also find most argument of that sort tedious, especially given the
multitude of factors unrelated to pure bat-and-ball, like contract status,
compensatory draft picks, differing locations in the competitive cycle, and so
forth. There's also information we're not privy to -- medical reports on
everyone involved (including everyone peripherally involved, like the other A's
outfielders) , an understanding of Mazzaro's mental and emotional state,
scouting reports on Marks, and future plans (no trade or signing is one-off --
there is always a larger agenda into which a given transaction fits).

All that said, I am pleased with the trade, even just from a pure fan's
perspective -- I've long admired DeJesus's game and I'd grown rather tired of
Vin Mazzaro's ball-in-play stylings, so, seeing as how the minor leaguer
involved isn't a stud waiting to happen, I'm feeling positive.

One last note: Baseball-Reference's implementation of Bill James's similarity
scores lists DeJesus's third-most-similar batter (and second-most-similar
through age 30) as Coco Crisp. (His 9th-best comp, by the way, is good ol'
Pistol Pete Reiser, the great Dodgers outfielder of the '40s who led the league
in OPS in 1941, went to war from '43 to '45, and was washed up at 29, mainly
because he couldn't stop crashing into walls. Ring Lardner, if I remember
correctly, wrote a great profile, and this Steven
Goldman piece at Baseball Prospectus is also recommended.)